This invention relates to workpiece positioning devices for use in computer controlled machining centers and, more particularly, to such devices which provide for rotation of the workpiece about an additional axis for the machining of compound angle features on the workpiece.
Four axis machining centers provide for relative movement between a workpiece and a tool in three mutually orthogonal directions (X, Y and Z axes in a Cartesian coordinate system) and rotation about the center line of one of the linear axes. Such machining centers are extremely versatile and can perform a wide range of machining operations. However, when compound angle features of the workpiece must be machined, a fifth axis is required. The required workpiece positioning can be accomplished manually through the use of a custom designed fixture for holding the workpiece. Where the workpiece includes more than one compound angle feature that must be machined, separate fixtures are required for each of the workpiece features.
Alternatively, a five axis machining center can be used to machine multiple compound angle features on a workpiece. Five axis machining centers are considerably more complex and expensive than four axis machining centers. It is therefore desirable to devise a workpiece positioning fixture which would permit the automated machining of multiple compound angle workpiece features in a four axis machining center.